Wal*Mart Office Supplies

I found these at Wal*Mart in the office supplies by the staples. They are really awesome for slings and they come in various sizes. I think these are really good for terrestrial slings, as I have my little B. smithi and my trouble-making C. marshalli in them. They're 88 cents each and are stackable. I poked holes in the sides and top with a push pin, and made sure the substrate was below the holes.